Component lifecycle in ReactJS | React Tutorials

Component lifecycle in ReactJS

1. Initialization
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defaultProps - set default props

constructor - set the initial state value and bind actions

componentWillMount - called before the render method is executed. It is important to note that setting the state in this phase will not trigger a re-rendering.

render - returns the needed component markup

componentDidMount - enabling to define DOM manipulations or data fetching operations.

2. State Changes
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shouldComponentUpdate - called before the render method and enables to define if a re-rendering is needed or can be skipped.

componentWillUpdate - called as soon as the shouldComponentUpdate returned true.

render - returns the needed component markup

componentDidUpdate - called after the render method. Similar to the
componentDidMount, this method can be used to perform DOM operations after the data has been updated.

Props Changes
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componentWillRecieveProps - called when the props have changed and when this is not an initial rendering. componentWillReceiveProps enables to update the state depending on the existing and upcoming props, without triggering another rendering.

shouldComponentUpdate - called before the render method and enables to define if a re-rendering is needed or can be skipped.

componentWillUpdate - called as soon as the
shouldComponentUpdate returned true.

render - returns the needed component markup

componentDidUpdate - called after the render method. Similar to the componentDidMount, this method can be used to perform DOM operations after the data has been updated.

Unmounting
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componentWillUnmount - called before the component is removed from the DOM. This method can be beneficial when needing to perform clean up operations, f.e. removing any timers defined in componentDidMount.